If I were you, I would call my doctor tonight after hours and ask about stopping or changing medicine dose since you are unsure. Get guidance from the doctor. If when you call tonight, he/she says you need to discuss it with an endo, ask him/her to call a colleague, if necessary to get an answer for you. Also, if your doctor is referring you out, surely they can make the call for you, doctor's office to doctor's office, to set up an appointment.
Also, when taking significant doses of thyroid meds, it is quite common for the TSH to become suppressed below the range. This doesn't mean that you have become hyperthyroid, unless you have hyper symptoms, due to excessive levels of the biologically active thyroid hormones, Free T3 and free T4 (not the same as Total T3 and T4). Unfortunately many doctors do not understand this and want to reduce meds, just as your doctor did.
So, please tell us about any symptoms you are having. Also, if you have been tested beyond TSH, please post your thyroid related test results and reference ranges shown on the lab report, so that members can better assess the adequacy of your testing and treatment.
>Has anyone ever seen a perfectly managed thyroid need to decrease meds during pregnancy, and if so, by how much?
Read some comments that for women that are hypothyroid medication
needs peek in the first trimester and then decrease. In any pregnancy weird stuff is afoot.
I wouldn't change anything right now without someone telling to to. I think because the meds you are on take last a week or so in your blood, stopping a dose won't help, but might confuse things for the doctor.
Also TSH in most people responds strongly to your actual hormone levels, so your probably not very hyperthyroid if at all.